This stamp comes in the famous "blue
paper" variety. The "blue" is actually
a "gray color", not really "blue", although it may take
on a slightly bluish tint. The stamp was made with a higher percentage of
rag content (about 30%) resulting in a grayish tinge.
The 4¢ "blue paper" was never issued for general use. Only one
pane escaped destruction and, according to
Johl, most of this pane of 100 are known, all unused. If
you think your stamp is the "blue paper" variety, you MUST have
the stamp certified. The 4¢ "blue paper" is one of the
great rarities of 20th century U.S. postage stamps.
